"(Transit officials) had to make a tough decision under significant pressure, and the decision was made to carry on to the next station," Ron Gabruck, the security chief for Edmonton Transit, told reporters Monday.
"Sometimes we have to make these decisions. That's the nature of our reality."
Gabruck said the broad-daylight attack by one man on passenger John Hollar in front of about 15 fellow transit riders had already begun when the train pulled into the north-end Belvedere station last Friday afternoon.
At the station, the doors opened and the other passengers fled, but the attack raged on.
"Most people when they're involved in a crime will commit the crime and then flee. This person had that opportunity. He chose to stay on the train," said Gabruck.
Gabruck said transit officials were aware by then what was happening.
They had to make a tough call: keep the train at the station with the doors open and hope the attacker gives up the fight, flees and can eventually be caught; or seal the doors and continue on three minutes to the next station at Clareview, where police and first aid were close by.
Gabruck said the train driver was ordered to drive on to Clareview. For the next three minutes, the beating continued in the otherwise empty car, visible on the driver's monitor.
"It's all about safety and quick response. And when I mean safety, I mean the safety of the victim as well," said Gabruck.
"We knew the ambulance stations are very close to Clareview as is the police station. We knew we had resources that could step in and help at that location, and so the decision was made."
When the train arrived at Clareview, the accused was arrested by police and transit officials while trying to escape.
Inside the car, the 29-year-old Hollar was found unconscious on the floor with severe brain injuries.
Hollar was dispatched to hospital and put on life support, but died Sunday night.
An autopsy Monday confirmed the death to be a homicide. Gabruck said it's the first on Edmonton's light-rapid transit train in its 34-year-history.
He agreed it was distressing event for the train car driver to go through, but said, "He's doing OK under the circumstances."
Homicide Det. Colin Derksen said the entire episode was caught on the train's video cameras, and he said it appeared to have been unprovoked.
"This was an attack," said Derksen.
"From what we can see (on the videotape), from the beginning of the fight to end it seemed very one-sided.
"(The attacker) was the aggressor and he continued that violence throughout and it appears that Mr. Hollar was trying just to avoid the situation and get away."
He said the victim and attacker may know each other, based on conversations police have had with those who know them both, but admitted, "We don't know for sure."
Derksen said there was no weapon involved and couldn't say if drugs were a factor.
He offered few details on the attack, as police still hope for other eyewitnesses to come forward.
He said two passengers tried to intervene, but wouldn't elaborate.
"(They) did what they could to stop this while still trying to keep themselves safe," he said.
"Unfortunately it didn't stop it."
Jeremy Newborn, 29, faces a charge of second-degree murder.